1. Field of the Invention
The present invention relates to a combined cycle power generation plant, constructed by combining a gas turbine unit and a steam turbine unit, in which a stabilizing burner is incorporated in a waste heat recovery boiler thereof.
2. Description of the Prior Art
A combined cycle power generation plant is a power generation system constructed by combining a gas turbine unit and a steam turbine unit. A high temperature range of the power generation plant thermal energy is used by the gas turbine, and a low temperature range is used by the steam turbine. Thus, the thermal energy is recovered and used effectively, so that this type of power generation system has recently come to be widely used.
In such combined cycle power generation plant, it is an active tendency to employ a steam cooling method for cooling the gas turbine, steam turbine, etc. using a cooling medium comprised of steam generated in its own cycle. That is, according to this steam cooling method, a high temperature portion of the gas turbine, for example, is cooled by steam, and the thermal energy obtained thereby is recovered by a bottom cycle of the steam turbine. Consequently, a highly advantageous system having an enhanced thermal efficiency can be obtained.
However, in order to effect a restart of the plant after the plant has been stopped (such as for a plant start-up after completion of inspection work, a weekly start and stop (WSS) in which a start and stop of operation are done in weekly intervals, or a daily start and stop (DSS) in which a start and stop of operation are done in daily intervals), the steam for cooling must be obtained from outside of the plant's own cycle. For example, the plant must depend on the steam from an auxiliary boiler which is installed outside.
In order to obtain the steam, which is needed at the time the plant is restarted after the plant has been stopped, various additional facilities are needed. This results in a complex plant, increased cost, and troublesome operation. On the other hand, if dependence on the auxiliary boiler is avoided by only waiting for steam generation at the waste heat recovery boiler while the gas turbine is held in start-up and during speed increases, then an unfavorable situation occurs from the view point of resonance of the compressor and turbine blades.